package com.atguigu.gulimall.product.service.impl;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.Comparator;
import java.util.List;
import java.util.Map;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.atguigu.common.utils.PageUtils;
import com.atguigu.common.utils.Query;

import com.atguigu.gulimall.product.dao.CategoryDao;
import com.atguigu.gulimall.product.entity.CategoryEntity;
import com.atguigu.gulimall.product.service.CategoryService;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {
//    @Autowired
//    CategoryDao categoryDao;

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    @Override
    public List<CategoryEntity> listWithTree() {
        //1.查出所有分类，null代表没有查询条件
        List<CategoryEntity> entities = baseMapper.selectList(null);


        //2.组装成父子的树形结构
        //2.1找到所有的一级分类，Cid=0的是父类
//        List<CategoryEntity> level1Menus = entities.stream()
//                .filter(categoryEntity -> categoryEntity.getParentCid() == 0)
//                .map((menu)->{ menu.setChildren(getChildrens(menu,entities));
//            return menu;
//        }).collect(Collectors.toList());

        List<CategoryEntity> level1Menus = entities.stream()
                .filter(categoryEntity -> categoryEntity.getParentCid() == 0)
                .map(menu -> { menu.setChildren(getChildrens(menu,entities));
                   return menu; })
                .sorted((menu1, menu2) -> (menu1.getSort()==null?0:menu1.getSort()) - (menu2.getSort()==null?0:menu2.getSort()))
                .collect(Collectors.toList());

        return level1Menus;
    }
    //该方法用于提取子菜单，并用于为前面的menu设置为子菜单
    private List<CategoryEntity> getChildrens(CategoryEntity root,List<CategoryEntity> all){
        List<CategoryEntity> children = all.stream()
                .filter(categoryEntity -> categoryEntity.getParentCid()==root.getCatId())
                .map(categoryEntity -> {
                    //递归找子菜单
                    categoryEntity.setChildren(getChildrens(categoryEntity, all));
                    return categoryEntity;
                }).sorted((menu1, menu2) -> {
                    //菜单的排序
                    return (menu1.getSort()==null?0:menu1.getSort()) - (menu2.getSort()==null?0:menu2.getSort());
                }).collect(Collectors.toList());

        return children;
    }
}